Method for separating, recycling and reusing FTrPSA in etching tail gas containing HF/HCl
A technology for tail gas and etching, applied in hydrogen separation, chemical instruments and methods, using solid contact hydrogen separation, etc., can solve the problems of non-recycling, general treatment effect, high cost, etc., and reduce the cost of raw materials and environmental protection treatment of tail gas. Effect
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Embodiment 1
[0044] Such as figure 1 Shown, a kind of method containing HF / HCl etching tail gas FTrPSA separation and recycling recycling, raw material gas, from the tail gas produced by silicon-based wafer chip dry etching process, mainly contains inert carrier gas hydrogen (H 2 ) 83% (v / v), effective components hydrogen fluoride (HF) 9% and hydrogen chloride (HCl) 5%, and a small amount of water (H 2 O), silicon tetrafluoride (SiF 4 ), silicon tetrachloride (SiCl 4 ), silane (SiH 4 ), methane (CH 4 ), carbon monoxide (CO), carbon dioxide (CO 2 ), and trace or trace amounts of volatile organic compounds (VOCs), metal ions (Me+), fine solid and aerosol particles (SS), and some impurity components of high fluorosilane acid / high chlorosilane, at normal temperature and pressure.
[0045] The specific implementation steps include,
[0046] (1) Pretreatment, the raw material gas is pressurized and sent to the pretreatment unit consisting of dust collector, particle filter, oil mist collec...
Embodiment 2
[0055] Such as figure 2 As shown, on the basis of Example 1, when the HCl concentration in the feed gas is less than 1%, and the HF concentration increases to about 13%, the purified feed gas directly enters the medium temperature pressure swing adsorption process, and the crude HF gas flowing out from the top of the 1#PSA tower , the condensed non-condensable gas 2 is exported through precision filtration and deionized water absorption to obtain a 40% HF aqueous solution, and the non-condensable gas 3 formed after water absorption is exported as hydrogen-rich gas and used as fuel gas. The crude HF liquid formed after condensation enters HF rectification after precision filtration, and the desorption gas flowing out from the bottom of the 1#PSA adsorption tower in the desorption step is pressurized to 0.2-0.3MPa and then from the 2#PSA The bottom of the adsorption tower enters, and the intermediate gas of the non-adsorbed phase flowing out from the top of the 2#PSA adsorption...
Embodiment 3
[0057] Such as image 3 As shown, on the basis of Example 1, the HF concentration (5%) in the feed gas is less than the working condition of the HCl concentration (9%), and the purified feed gas from the pretreatment process enters the Chlorosilane / HCl spray absorption process, the non-condensable gas 1 flowing out from the top of the spray absorption tower, the non-condensable gas 2 formed after condensation, then enters the medium temperature pressure swing adsorption process composed of two stages of PSA, and forms after condensation The condensed liquid directly enters the HCl refining process, and the absorption liquid flowing out from the bottom of the spray absorption tower enters the multi-stage evaporation / compression / condensation process.
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